Make module_test runner & example handle failures correctly

The existing runner.js wouldn't exit w/ a non-zero code if either a test
fails, or cypress.run threw an exception. This will handle both cases

Fixes #44

cypress/tests/module_test/runner.js

@@ -1,9 +1,26 @@
 const cypress = require('cypress')
 
-cypress.run({
-  headless: true,
-}).then(result => {
-  if (result.status === 'failed') {
-    process.exit(1);
-  }
-})
+async function main() {
+    try {
+        const result = await cypress.run({
+            headless: true,
+        })
+
+        // If any tests have failed, results.failures is non-zero, some tests have failed
+        if (result.failures) {
+            console.error('One or more cypress tests have failed')
+            console.error(result.message)
+            process.exit(1)
+        }
+
+        if (result.status !== 'finished') {
+            console.error('Cypress tests failed with status', result.status)
+            process.exit(2)
+        }
+    } catch (e) {
+        console.error("Cypress encountered unexpected exception. Exiting.", e)
+        process.exit(3)
+    }
+}
+
+main();